
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.Enumeration;
import java.util.Objects;
@WebServlet("/show")//一个 Servlet类只能有一个@WebSwevlet注解
public class ShowRequestServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//        拼接成字符串 返回给客户端
        StringBuilder stringBuilder = new StringBuilder();
        stringBuilder.append(req.getProtocol());
        stringBuilder.append("<br>");
        stringBuilder.append(req.getMethod());
        stringBuilder.append("<br>");
        stringBuilder.append(req.getRequestURI());
        stringBuilder.append("<br>");
        stringBuilder.append(req.getContextPath());
        stringBuilder.append("<br>");
        stringBuilder.append(req.getQueryString());
        stringBuilder.append("<br>");

//        获取所有的 header
        Enumeration<String> headerNames = req.getHeaderNames();
        while(headerNames.hasMoreElements()){
            String key = headerNames.nextElement();
            String value = req.getHeader(key);
            stringBuilder.append(key + ":"+value+"<br>");
        }
//        告诉浏览器 数据类型
        resp.setContentType("text/html;charset=utf8");
//        将上述内容整体返回到客户端
        resp.getWriter().write(stringBuilder.toString());

    }
}
